Unmanned aerial vehicles (UAVs) comprise a variety of vehicles, from conventional fixed wing airplanes, to helicopters, to ornithopters (i.e., machines that fly like birds), and are used in a variety of roles. They can be remotely piloted by a pilot on the ground or can be autonomous or semi-autonomous vehicles that fly missions using preprogrammed coordinates, global positioning system (GPS) navigation, etc. UAVs also include remote control helicopters and airplanes used by hobbyists.
UAVs can be equipped with cameras to provide imagery during flight, which may be used for navigational or other purposes (e.g., to identify a house address). UAVs can also be equipped with sensors to provide local weather and atmospheric conditions, radiation levels, and other conditions. UAVs can also include cargo bays, hooks, or other means for carrying payloads.
Newer generation UAVs can also provide significant payload capabilities. As a result, UAVs can also be used for delivering packages, groceries, mail, and other items. The use of UAVs for deliveries can reduce costs and increase speed and accuracy. However, landing a UAV at a delivery location may be problematic for multiple reasons, such as the presence of obstacles (e.g., trees, power lines, etc.) and the power requirements of descending and ascending from the delivery location, among other reasons.